I have a P1 DF+, LS 80mm and P40+ back . I purchased a new battery for the DF+ about 18 months ago and it seems to work fine until a couple of weeks ago. I would be able to get 15 or 20 shots before the camera would shut off. The DF+ battery would be drained and the back would still be functional.
So of course I thought it was the battery, so I was able to get my hands on two other batteries, but still couldn't get more than 20 or 30 shots before the camera shuts off. Any advise would be greatly appreciated as my next step will be to send the camera off for service/troubleshooting.